1. Field of the Invention
The present invention relates to a decompression technique for decompressing data compressed by using a compression technique based on dictionary method.
2. Description of the Related Art
In recent years, the amount of data to represent an image, a character and the like is becoming larger, and data compression is performed for the purpose of storage and transmission. For example, an LZW compression technique is known in Japanese Patent Application Laid-Open No. 2001-267930.
The above-described LZW is an improved LZ78 type compression technique, and these compression techniques are called compression techniques based on dictionary method. Generally, when this type of encoded data is decompressed, it is necessary to perform processing of sequentially registering a character string, which might be restored, in a “dictionary (table)”. However, since a character string potentially restored is registered in the dictionary, such character string registered in the dictionary is not necessarily utilized. That is, the technique is still susceptible to improvement in terms of efficiency in use of the dictionary, i.e., reduction of memory capacity consumption.